System.Data.ConstraintException: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.
In my case this happened because we did not include any of the primary keys in table joins.
You may want to try this using your DataSet Designer.
- Open the dataset designer
- Go to the TableAdapter in question
- Find where the primary key is set
- Right click over and select Primary Key menu
- Change the key to something else that make more sense